PENSION AND OTHER POSTRETIREMENT PLANS - Schedule of Fair Values of Pension Plan and Postretirement Plan Assets by Asset Category (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	$ 2,470	$ 2,148
SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	913	884
Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	2,470	2,148
Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	913	884
Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US large cap common stocks [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	912	784
Equity securities - US large cap common stocks [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	353	322
Equity securities - US large cap common stocks [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	912	784
Equity securities - US large cap common stocks [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	353	322
Equity securities - US large cap common stocks [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US large cap common stocks [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US large cap common stocks [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US large cap common stocks [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US mid cap stock mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	115	107
Equity securities - US mid cap stock mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	46	43
Equity securities - US mid cap stock mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	115	107
Equity securities - US mid cap stock mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	46	43
Equity securities - US mid cap stock mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US mid cap stock mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US mid cap stock mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US mid cap stock mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US small cap stock mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	119	114
Equity securities - US small cap stock mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	47	43
Equity securities - US small cap stock mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	119	114
Equity securities - US small cap stock mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	47	43
Equity securities - US small cap stock mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US small cap stock mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US small cap stock mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - US small cap stock mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - international stock mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	257	225
Equity securities - international stock mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	100	89
Equity securities - international stock mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	257	225
Equity securities - international stock mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	100	89
Equity securities - international stock mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - international stock mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - international stock mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity securities - international stock mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity Securities - emerging markets stock mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	111	49
Equity Securities - emerging markets stock mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	43	18
Equity Securities - emerging markets stock mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	111	49
Equity Securities - emerging markets stock mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	43	18
Equity Securities - emerging markets stock mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity Securities - emerging markets stock mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity Securities - emerging markets stock mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Equity Securities - emerging markets stock mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - intermediate term bond mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	402	309
Debt securities - intermediate term bond mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	156	123
Debt securities - intermediate term bond mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	402	309
Debt securities - intermediate term bond mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	156	123
Debt securities - intermediate term bond mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - intermediate term bond mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - intermediate term bond mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - intermediate term bond mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - short term bond mutual funds [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	480	543
Debt securities - short term bond mutual funds [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	155	231
Debt securities - short term bond mutual funds [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	480	543
Debt securities - short term bond mutual funds [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	155	231
Debt securities - short term bond mutual funds [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - short term bond mutual funds [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - short term bond mutual funds [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Debt securities - short term bond mutual funds [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Cash - money market account [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	74	17
Cash - money market account [Member] | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	13	15
Cash - money market account [Member] | Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	74	17
Cash - money market account [Member] | Level 1 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	13	15
Cash - money market account [Member] | Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Cash - money market account [Member] | Level 2 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Cash - money market account [Member] | Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Cash - money market account [Member] | Level 3 | SERP Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits	$ 0	$ 0